Compilare: user.cpp:87:14: warning: multi-character character constant [-Wmultichar] g << '-1'; ^ user.cpp: In function ‘bool iseuler()’: user.cpp:24:20: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if (grd[n] & 1 == 1) { ^ user.cpp: In function ‘void euler()’: user.cpp:47:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[nd].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:83:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol.size(); i++) { ^